SiO2纳米颗粒对小球藻(Chlorella pyrenoidosa)生长活性的影响

从Si02纳米颗粒对小球藻(Chlorella pyrenoidosa)生长活性的影响来探讨纳米材料的生物安全性问题.结果表明Si02纳米颗粒降低了小球藻的生物量和蛋白含量,并可以附着在细胞表面和进入细胞内部,造成了细胞的形变和结构损伤,从而抑制了小球藻的正常生长活性.Si02纳米颗粒对小球藻具有一定的毒性效应.     

厌氧消化过程中镍及其螯合物的生物可利用性研究

通过厌氧消化静态实验,研究了不同螯合剂存在条件下,产甲烷富集培养物对微量元素镍及其螯合物的生物吸收.结果表明,螯合剂的种类对厌氧消化有着一定影响.在乙酸钠浓度为85 mmol/L,硫化物浓度为1 mmol/L,消化温度为35℃,镍离子浓度为200 μmol/L时,氨三乙酸(NTA)的添加体系中甲烷产量最高,分别比柠檬酸...     

镍对厌氧消化过程的抑制作用研究

采用混合式厌氧反应器,以酒糟废水为基质,在相同条件的不同反应器中每日加入不同浓度的镍离子（以硝酸镍形式加入）,研究不同浓度的镍离子对厌氧体系的抑制作用,以及体系中溶解态的镍离子含量与抑制程度的关系。结果表明,日加入镍量低于３６．４ｍｇ／Ｌ时,对体系无影响;在４０－６０ｍｇ／Ｌ时,产生轻微的抑制;超过８０ｍｇ／Ｌ时,对体系造成严重的抑制。当体系中溶解态镍离子浓度低于２．５ｍｇ／Ｌ时,体系不受影响。厌     

化学镀镍废液的处理及再生技术研究进展

介绍了化学镀镍废液的产生和危害,综述了近年来国内外采用化学沉淀法、电解法、氧化还原法、萃取法、离子交换法、电渗析法等对化学镀镍废液进行处理及净化再生的技术研究进展,对各种方法的实用性进行了评价,并指出今后的发展方向。     

龙口褐煤对Ni^2＋,Mn^2＋,Hg^2＋等重金属离子的吸附特性

本文以龙口褐煤作吸附剂,对重金属离子Ｎｉ＾２,Ｍｎ＾２＋,Ｈｇ＾２＋的单组分水溶液进行吸附研究,探讨了吸附剂的吸附性能,影响吸附的因素和吸附机理。结果表明：褐煤对Ｎｉ＾２＋,Ｍｎ＾２＋,Ｈｇ＾２＋的吸附均表现出Ｌａｎｇｍｕｉｒ特征,ＰＨ值是影响吸附的一个重要因素。     

水样中镉镍的两次双波长分光光度法测定

研究采用两次双波长分光光度法 ,一次采用双峰双波长法 ,一次采用系数补偿法同时测定水样中的镉和镍。实验结果表明 ,以 5 Br PADAP为显色剂 ,镉和镍的最大吸收峰分别为 544 .8nm和 559.2nm ,最小吸收峰均为 430nm ;镉镍的线性范围为 1～ 1 6μg/ 2 5mL。此法的灵敏度同单波长法相比有明显的提高 ,应用于合成和电镀水样中的镉镍的测定 ,均得到了满意的结果。     

Rapid treatment of atrazine-contaminated water by nickel/iron bimetallic system

The utility of nickel/iron in the remediation of atraz.ine-contaminated water was investigated. The experimental results showed that nickel/iron had effective catalytic activity in dechlorinating atraz.ine under acidic conditions. The dechlonnation reaction approximately followed the first-order kinetics under the experimental conditions( nickel/iron: 1.0 g/250 ml: Ca~r~ = 20.0 mg/L), the reaction rate increased with decreasing pH value of the reaction solution and increasing the proportion of Ni: Fe within 2.95 %. For condition with 2.95% nickel/iron, the reaction rate constants were 0.07518( R = 0.9927), 0.06212( R = 0.9846) and 0.00131 min^-1 ( R = 0.9.565) at pH = 2.0, 3.0 and 4.0, respectively. HPLC analysis was used to monitor the decline of atraz.ine concentration.     

Preconcentration of cadmium and copper ions on magnetic core–shell nanoparticles for determination by flame atomic absorption

Magnetic core–shell nanoparticles modified by (3-aminopropyl) trimethoxy silane were prepared and used as adsorbent for the extraction and preconcentration of cadmium and copper ions. The ions were desorbed with nitric acid followed by determination with flame atomic absorption spectrometry. The extraction conditions were investigated systematically. The method was applied for the determination of Cd(II) and Cu(II) ions in different water samples. The accuracy was also evaluated through analysis of certified reference material.     

Effect of two TiO2 nanoparticles on the growth of unicellular green algae using the OECD 201 test guideline: influence of the exposure system

This work aimed at assessing the influence of different exposure systems to perform the commonly used OECD 201 freshwater algal growth inhibition test in the context of nanoparticles hazard assessment. Two distinct TiO₂ nanoparticles were considered and three different exposure systems were investigated: Erlenmeyers flasks and 24-well microplates (both using an orbital shake system), and an alternative system using cylindrical vials and magnetic stirring. All three systems are in accordance with the OECD 201 test guideline recommendations. We concluded that the exposure systems applied to achieve the test can substantially affect the ecotoxicological results and the subsequent calculated ECx. The selected systems influenced both the interaction between algal cells and TiO₂ nanoparticles as well as the growth inhibition recorded. Disparities in ecotoxicity relative to the TiO₂ nanoparticles tested were also observed and are finally discussed.     

不同老化时间的TiO_2纳米颗粒对玉米生长的影响

为探讨老化时间对TiO_2纳米颗粒(nanoparticles,NPs)生物有效性的影响,研究了不同老化时间的Ti O_2NPs(0~120 d)对玉米幼苗生长的影响、在玉米体内的吸收及其在植株不同部位的存在位点等。研究发现,不同浓度的TiO_2NPs(1 000 mg·kg~(-1)和2 000 mg·kg~(-1))加入到土壤中,对玉米幼苗干鲜重没有明显的影响,但老化时间小于60 d时,对玉米幼苗株高有一定的抑制效应,老化60 d之后,随着老化时间的继续延长,毒性逐渐降低,最后趋于稳定。老化60 d时,TiO_2NPs处理的玉米幼苗根冠增大,玉米幼苗体内产生H2O_2的累积。在Ti O_2老化土壤中生长的玉米幼苗根系和地上部均有Ti的累积,1 000 mg·kg~(-1)的TiO_2NPs在玉米幼苗根部的生物累积系数达到35.4%,在地上部为13.6%,在玉米植株体内的转运系数为0.38;通过TEM观察,TiO_2NPs可以进入到玉米幼苗体内,并存在于根细胞的细胞质和叶绿体膜上,在叶片细胞的液泡和细胞核中也发现有TiO_2NPs的存在。上述研究结果为客观评价TiO_2NPs的生态风险提供了有用信息。